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3x squared minus 6x plus 11=0

 Jun 9, 2015

Best Answer 

 #2
avatar+33661 
+10

The quadratic formula is:

 

$$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$$

 

Your equation only has complex roots:

$${\mathtt{3}}{\mathtt{\,\times\,}}{{\mathtt{x}}}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{6}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{11}} = {\mathtt{0}} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{\,-\,}}{\frac{\left({\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{6}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,-\,}}{\mathtt{3}}\right)}{{\mathtt{3}}}}\\
{\mathtt{x}} = {\frac{\left({\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{6}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,\small\textbf+\,}}{\mathtt{3}}\right)}{{\mathtt{3}}}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{\,-\,}}\left({\mathtt{\,-\,}}{\mathtt{0.999\: \!999\: \!999\: \!999\: \!821}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1.632\: \!993\: \!161\: \!854\: \!606\: \!3}}{i}\right)\\
{\mathtt{x}} = {\mathtt{0.999\: \!999\: \!999\: \!999\: \!821}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1.632\: \!993\: \!161\: \!854\: \!606\: \!3}}{i}\\
\end{array} \right\}$$

 

The calculator here has introduced some rounding error; the 0.99999.... parts should be exactly 1

.

.

 Jun 9, 2015
 #1
avatar+55 
0

No real solutions...

Let's solve your equation step-by-step.
3x2−6x+11=0
Step 1: Use quadratic formula with a=3, b=-6, c=11.
x=−b±b2−4ac2a
x=−(−6)±(−6)2−4(3)(11)2(3)
x=6±−966
 
 
 Jun 9, 2015
 #2
avatar+33661 
+10
Best Answer

The quadratic formula is:

 

$$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$$

 

Your equation only has complex roots:

$${\mathtt{3}}{\mathtt{\,\times\,}}{{\mathtt{x}}}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{6}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{11}} = {\mathtt{0}} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{\,-\,}}{\frac{\left({\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{6}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,-\,}}{\mathtt{3}}\right)}{{\mathtt{3}}}}\\
{\mathtt{x}} = {\frac{\left({\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{6}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,\small\textbf+\,}}{\mathtt{3}}\right)}{{\mathtt{3}}}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{\,-\,}}\left({\mathtt{\,-\,}}{\mathtt{0.999\: \!999\: \!999\: \!999\: \!821}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1.632\: \!993\: \!161\: \!854\: \!606\: \!3}}{i}\right)\\
{\mathtt{x}} = {\mathtt{0.999\: \!999\: \!999\: \!999\: \!821}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1.632\: \!993\: \!161\: \!854\: \!606\: \!3}}{i}\\
\end{array} \right\}$$

 

The calculator here has introduced some rounding error; the 0.99999.... parts should be exactly 1

.

.

Alan Jun 9, 2015

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